CVE-2009-1956

Exp

Off-by-one error in the apr_brigade_vprintf function in Apache APR-util before 1.3.5 on big-endian platforms allows remote attackers to obtain sensitive information or cause a denial of service (application crash) via crafted input.

Published: 2009-06-07 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2009-1956 is rated High Exploit Risk (79.1/100): CVSS Medium severity, with high exploitation likelihood (EPSS 12.04%, 96th percentile). 2 public exploit reference(s) are indexed (Exploit-DB). EPSS rose +6.63% over the last day, indicating growing attacker interest. Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2009-1956

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2009-1956

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 5.42% 12.04% +6.63%
2 2026-03-04 4.27% 5.42% +1.14%
3 2025-12-28 — 4.27% —

Full EPSS history (22 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2009-1956

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.4 2.0 MEDIUM
AV:N/AC:L/Au:N/C:P/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 4.9 [email protected]

Weakness enumeration for CVE-2009-1956

OS Trackers for CVE-2009-1956

vendor priority summary link
debian low CVE-2009-1956 low priority: Debian including 1 source packages (apr-util), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2009-1956
gentoo normal CVE-2009-1956: 1 GLSA(s) (200907-03), 1 atom(s) (dev-libs/apr-util); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2009-1956
redhat medium — https://access.redhat.com/security/cve/CVE-2009-1956
suse medium CVE-2009-1956 severity moderate: SUSE including 78 source package names (apache2-2.4.10-6.1, apache2-2.4.16-5.1, …), 100 product×package rows across 22 product lines (SUSE Linux Enterprise High Performance Computing 12 SP5, SUSE Linux Enterprise Module for Server Applications 15, … (22 product lines)): Fixed 100. https://www.suse.com/security/cve/CVE-2009-1956/
ubuntu medium CVE-2009-1956 medium priority: Ubuntu including 2 source packages (apache2, apr-util), 10 status rows across 5 suites (dapper, hardy, intrepid, jaunty, upstream): released 5, not-affected 3, DNE 1, needs-triage 1. https://ubuntu.com/security/CVE-2009-1956

Affected software / configurations for CVE-2009-1956

Vendor Product Version Raw CPE
apache apr-util <= 1.3.4 cpe:2.3:a:apache:apr-util:*:*:*:*:*:*:*:*
apache http_server >= 2.2.0, < 2.2.12 cpe:2.3:a:apache:http_server:*:*:*:*:*:*:*:*
canonical ubuntu_linux 6.06 cpe:2.3:o:canonical:ubuntu_linux:6.06:*:*:*:*:*:*:*
canonical ubuntu_linux 8.04 cpe:2.3:o:canonical:ubuntu_linux:8.04:*:*:*:-:*:*:*
canonical ubuntu_linux 8.10 cpe:2.3:o:canonical:ubuntu_linux:8.10:*:*:*:*:*:*:*
canonical ubuntu_linux 9.04 cpe:2.3:o:canonical:ubuntu_linux:9.04:*:*:*:*:*:*:*

References for CVE-2009-1956

URL Tags
http://lists.apple.com/archives/security-announce/2009/Nov/msg00000.html Mailing List Third Party Advisory
http://marc.info/?l=bugtraq&m=129190899612998&w=2 Mailing List Third Party Advisory
http://secunia.com/advisories/34724 Broken Link
http://secunia.com/advisories/35284 Broken Link
http://secunia.com/advisories/35395 Broken Link
http://secunia.com/advisories/35487 Broken Link
http://secunia.com/advisories/35565 Broken Link
http://secunia.com/advisories/35710 Broken Link
http://secunia.com/advisories/35797 Broken Link
http://secunia.com/advisories/35843 Broken Link
http://secunia.com/advisories/37221 Broken Link
http://security.gentoo.org/glsa/glsa-200907-03.xml Third Party Advisory
http://support.apple.com/kb/HT3937 Third Party Advisory
http://svn.apache.org/viewvc?view=rev&revision=768417 Patch Third Party Advisory
http://www-01.ibm.com/support/docview.wss?uid=swg1PK88341 Third Party Advisory
http://www-01.ibm.com/support/docview.wss?uid=swg1PK91241 Third Party Advisory
http://www-01.ibm.com/support/docview.wss?uid=swg1PK99478 Third Party Advisory
http://www-01.ibm.com/support/docview.wss?uid=swg27014463 Third Party Advisory
http://www.apache.org/dist/apr/CHANGES-APR-UTIL-1.3 Vendor Advisory
http://www.mail-archive.com/dev%40apr.apache.org/msg21591.html
http://www.mail-archive.com/dev%40apr.apache.org/msg21592.html
http://www.mandriva.com/security/advisories?name=MDVSA-2009:131 Broken Link
http://www.mandriva.com/security/advisories?name=MDVSA-2013:150 Broken Link
http://www.openwall.com/lists/oss-security/2009/06/06/1 Exploit Mailing List Patch
http://www.oracle.com/technetwork/topics/security/cpuapr2013-1899555.html Third Party Advisory
http://www.redhat.com/support/errata/RHSA-2009-1107.html Third Party Advisory
http://www.redhat.com/support/errata/RHSA-2009-1108.html Third Party Advisory
http://www.securityfocus.com/bid/35251 Third Party Advisory VDB Entry
http://www.ubuntu.com/usn/usn-786-1 Third Party Advisory
http://www.ubuntu.com/usn/usn-787-1 Third Party Advisory
http://www.vupen.com/english/advisories/2009/1907 Permissions Required
http://www.vupen.com/english/advisories/2009/3184 Permissions Required
https://bugzilla.redhat.com/show_bug.cgi?id=504390 Exploit Issue Tracking Patch Third Party Advisory
https://lists.apache.org/thread.html/8d63cb8e9100f28a99429b4328e4e7cebce861d5772ac9863ba2ae6f%40%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/f7f95ac1cd9895db2714fa3ebaa0b94d0c6df360f742a40951384a53%40%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/r2295080a257bad27ea68ca0af12fc715577f9e84801eae116a33107e%40%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/r57608dc51b79102f3952ae06f54d5277b649c86d6533dcd6a7d201f7%40%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/r75cbe9ea3e2114e4271bbeca7aff96117b50c1b6eb7c4772b0337c1f%40%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/r9ea3538f229874c80a10af473856a81fbf5f694cd7f471cc679ba70b%40%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/r9f93cf6dde308d42a9c807784e8102600d0397f5f834890708bf6920%40%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/rad01d817195e6cc871cb1d73b207ca326379a20a6e7f30febaf56d24%40%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/rad2acee3ab838b52c04a0698b1728a9a43467bf365bd481c993c535d%40%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/rdca61ae990660bacb682295f2a09d34612b7bb5f457577fe17f4d064%40%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/reb7c64aeea604bf948467d9d1cab8ff23fa7d002be1964bcc275aae7%40%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/rf6449464fd8b7437704c55f88361b66f12d5b5f90bcce66af4be4ba9%40%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/rfbaf647d52c1cb843e726a0933f156366a806cead84fbd430951591b%40%3Ccvs.httpd.apache.org%3E
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A11567 Third Party Advisory
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A12237 Third Party Advisory
https://www.redhat.com/archives/fedora-package-announce/2009-June/msg01173.html Third Party Advisory
https://www.redhat.com/archives/fedora-package-announce/2009-June/msg01201.html Third Party Advisory
https://www.redhat.com/archives/fedora-package-announce/2009-June/msg01228.html Third Party Advisory
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